Conventionally, power conversion devices employ a high breakdown voltage transistor. Furthermore, there is also a method using a plurality of high breakdown voltage transistors connected in parallel to allow a power conversion device to have an increased rated current. In this method, the plurality of high breakdown voltage transistors are prevented from having a high breakdown voltage transistor with a low threshold voltage receiving a current intensively, as follows: Each high breakdown voltage transistor's current is sensed, and if the high breakdown voltage transistors have currents passing therethrough with a difference therebetween larger than a predetermined value, a gate resistance is reduced to be smaller than normal to turn on the high breakdown voltage transistors faster (see Japanese Patent Laying-Open No. 2002-095240 (PTD 1) for example).